Some medical techniques utilizing lasers can be performed with better and more optimal results by employing a laser which generates output laser light pulses having a relatively long duration. One such medical technique is selective photothermolysis which is used, for example, to treat cutaneous vascular lesions. In selective photothermolysis, targeted tissues are heated by laser light (e.g., light generated by a flashlamp-excited liquid dye laser) having a wavelength selected to be specifically absorbed by the targeted tissue. In treating cutaneous vascular lesions, the benefits afforded by a flashlamp-excited liquid dye laser (FEDL) which generates output laser light pulses of long duration include improved clearing of the lesion, fewer treatment sessions, reduced incidence of hyper pigmentation, and a reduced transient purpura.
Conventional flashlamp-excited lasers including flashlamp-excited dye lasers and FEDLs typically produce output laser light pulses lasting between approximately 0.1 and 100 microseconds. Attempts to extend the duration of the output light pulse of a FEDL beyond this range typically result in thermal optical distortions of a liquid dye medium of the FEDL which cause the laser action (i.e., "lasing") of the FEDL to self-terminate. These thermal optical distortions of the liquid dye medium are induced, in general, by the excitation provided to the flashlamp.